The present invention is concerned with a process for the homologation of carboxylic acid esters. More specifically, the present invention involves a process for the conversion of carboxylic acid esters to homologous carboxylic acid esters by reaction of the ester with hydrogen and carbon monoxide in the presence of a heterogeneous sulfided catalyst.
An article by M. Hidai et al. in Bull. Chem. Soc. Japan, volume 55, pages 3951-52 (1982) describes the homologation of methyl esters, in particular the conversion of methyl acetate to ethyl acetate, with synthesis gas in the presence of a homogenous ruthenium-cobalt catalyst and a methyl iodide promoter.
European Patent Application Publication No. 0031606 A1 describes the preparation of carboxylic acids and esters from carboxylic acid esters having one less carbon atom, carbon monoxide and hydrogen in the presence of a catalyst containing a ruthenium compound, a Group II metal iodide and/or bromide and a further Group VIII metal compound.
European Patent Application Publication No. 0031784 A2 describes the preparation of alkyl carboxylates from lower homologs by reaction with carbon monoxide and hydrogen using a ruthenium, cobalt and iodide catalyst system.
European Patent Application Publication No. 0046128 A1 describes the hydrocarbonylation and/or carbonylation of alkyl carboxylates in the presence of ruthenium, cobalt, vanadium and an iodide promoter.